NH_4HCO_3沉淀分离还原反萃余液中的稀土与锌工艺研究

Precipitation Separation of Rare Earth and Zinc from Stripping Residual Liquid of Reduction Extraction by Ammonium Bicarbonate

在还原萃取分离铕的反萃余液中加入NH_4Cl,用固体NH_4HCO_3与稀土反应生成碳酸稀土沉淀,而Zn与NH_4Cl形成配合物存在于母液中,实现反萃余液中稀土和锌的分离。考察了料液中NH_4Cl,RECl_3,Zn Cl_2浓度、沉淀终点p H和沉淀反应温度这些因素对碳酸稀土中Zn O含量的影响。实验结果表明:在料液中NH_4Cl浓度4 mol·L^(-1),RECl_3浓度0.34 mol·L^(-1),Zn Cl_2浓度不大于0.62 mol·L^(-1),反应温度50℃,沉淀终点p H为6.5条件下,得到的碳酸稀土中Zn O含量小于0.005%。

The separation of rare earth and zinc was achieved when the solid ammonium bicarbonate was reacted with rare earth to produce rare earth carbonate precipitation, and zinc and NHaCl formed a complex in the mother liquor by adding NH4Cl in the stripping residual liquid of the reduction extraction of europium. The influence of the concentrations of NH4 Cl, REC13 and ZnCI2 in the feed liquid, the final pH and the reaction temperature on the con- tent of ZnO in rare earth carbonate was investigated. The results showed that the concentrations of NH4 Cl, RECl3 and ZnCl2 successively were 4, 0.342 mol·L-1 and less than 0.615 mol·L-1 in the feed liquid, the reaction temperature was 50 ℃ and the final pH value was 6.5, the content of ZnO in the rare earth carbonate was less than 0. 005%.